Test 2 Review

Test 2 Review - Review of Lecture February 15 I....

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Review of Lecture February 15 I. Introduction to the Movement of Substances A. Movement of a substance between two places depends on the chemical potential energy of a substance at those two places . 1. Define energy and work . Energy-the ability to do work Work-the displacement of a substance against a force 2. Spontaneous movements always occur from a place of ???? chemical potential energy to a place of ????? chemical potential energy for a substance. Higher to lower 3. Non-spontaneous movements require the application of what to make them occur? An input of energy B. Chemical Potential Energy of a substance depends on at least four factors (A fifth factor affects substances that are charged, for example, K + , but you do not need to know this information for a test.) 1. What are these four factors ? Amount, Temperature, Pressure, Gravity 2. Be sure that you can explain in terms of chemical potential energy differences why a pen drops to the floor when it is released above the floor or why water moves spontaneously over the edge of a waterfall. C. Note any movements that are occurring around you . 1. Are they spontaneous or non-spontaneous? II. Water Movements in the Plant A. For water in a plant parenchyma cell , what two factors normally determine the chemical potential for water (water potential, Ψ )? 1. NOTE: These are the only factors that normally determine differences in water potential energy between inside and outside of a parenchyma cell, since factors, such as atmospheric pressure, are the same over these distances. 2. Remember that water always moves spontaneously in a plant . Therefore, we will only be interested in differences in Ψ between points in the plant at the cell or whole plant level . 3. Is the water purity higher for water in the cell or for pure water ? Higher for pure water B. Water Movement INTO a Plant Cell 1. Water movement into the cell depends on differences in water potential energy or water potential ( Ψ ) inside and outside of the cell. 2. When water is moving into a plant cell, is the Ψ inside of the cell greater or less than the Ψ for water outside ? Less than outside
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3. As water moves into the cell , Ψ rises because of changes in two factors. What are these factors? Changes in amount of water and cell wall pressure? a. Only a small increase in cell volume occurs. b. Under what condition related to the Ψ in and out will there no longer be any net movement of water in or out of the cell ? When the Ψ outside = Ψ inside 4. What would happen to your cells if you put them into pure water ? Nothing? Review of Lecture February 17 I. Water Movement OUT of a Plant Cell A. What would be the relative Ψ inside vs. outside of the cell in this case? Higher inside vs. lower outside? 1.
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Test 2 Review - Review of Lecture February 15 I....

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